Earlier quoted context omitted.
As mentioned in the OP, we now have wl-clipboard. :) Furthermore, it's proprietary NVIDIA drivers Wayland isn't supporting, not NVIDIA itself. AFAIK nouveau works just fine. There are many great reasons for not supporting the proprietary NVIDIA drivers.
Noveau sucks, unfortunately. Performance is bad, and you can't load custom firmware like you could with older cards (signing problems). I respect the effort the developers have made; any other driver would be of excellent quality had this much effort been put into it. But Nvidia keeps on being a jerk about it. Easy to say don't support Nvidia, but at the present moment they have the fastest consumer cards on the mark…
This is becoming a lot less true. Unless you really want to run the latest games (in which case you'll be on Windows anyway), nvidia is on equal footing as AMD nowadays on Linux. AMD has made a lot of efforts and progress the past few years, and them playing nicely with the OSS community makes a big difference.
My next computer will have an AMD card&processor.